The present invention relates to a system that recovers and purifies neon from exhaust gas discharged from, for example, a semiconductor manufacturing apparatus having an excimer laser mounted thereon, and to a system installed in a factory in which a semiconductor manufacturing apparatus is installed and a neon recovering/purifying method.
JP-A-2001-232134 describes an example neon recovering apparatus that recovers high-purity neon from gas discharged from a KrF excimer laser oscillator.
Moreover, JP-A-2010-241686 describes that, when high-value added gas of at least one kind of krypton, xenon, and neon is separated and purified for recovering from exhaust gas discharged from a manufacturing facility for semiconductor products or display apparatuses that uses the high-value added gas as atmospheric gas, a slight amount of impurities such as nitrogen oxide, ammonia, oxygen, nitrogen, hydrogen, helium, and moisture contained in the exhaust gas are efficiently removed, and the high-value added gas is continuously separated and purified for recovering with a high recovery rate.
The following is described in JP-A-2001-232134. Because the amount of exhaust gas discharged from a KrF excimer laser oscillator in one factory is not large, it is more efficient to put together and purify exhaust gases from several factories, compared with installing the neon recovering apparatus as one facility in each factory. Hence, exhaust gas is once stored in a gas cylinder, and is transported to another gas purifying factory. Then, a neon recovering process is performed on the transported gases all together by the neon recovering apparatus installed in the gas purifying factory. In this way, efficient recovery is achieved.
The following is described in JP-A-2010-241686. Ammonia and moisture are removed using an adsorbent from exhaust gas discharged from a semiconductor manufacturing facility. Subsequently, high-value added gas (such as neon) is selectively adsorbed onto an adsorbent from the exhaust gas, and the high-value added gas is desorbed.
Further, impurities are removed by adsorption using an adsorbent onto which the high-value added gas (neon) is not easily adsorbed. In this way, the high-value added gas is separated and purified. That is, in addition to the adsorption of the impurities other than the high-value added gas, even the high-value added gas is selectively adsorbed.
Hence, complicated steps are necessary, and costs for the separation and purification are inevitably high.